One of the ways to improve your Google PageRank is to limit the number of link juice you have flowing out of your root site and to other pages, this includes links to internal page resources. I found a nice wordpress plug-in called “Noindex/Nofollow Links” which will automatically no follow all your category and archive links from your homepage, so you aren’t leaking out your PR juice to twenty or thirty internal pages.
I just implemented this plug-in a few days ago on all of my blogs which currently are a DB PR0, JG PR1, RAP PR2 and WT PR2 respectively,so I don’t know if this will help until the next PageRank update which probably will be around August. But a fellow blogger I know was able to get his blog bumped up to a PageRank 3 by closing all links outbound on his homepage and this looks to be a good place to start.
Once you download the plug-in (link in first paragraph), you install it in your wordpress blog, click on the “Noindex/Nofollow links” in your Settings section, and then you can check mark nofollow or noindex to your Archive Links, Tag Links or Category Links.